Electric coolant pump with heating element

ABSTRACT

An electric coolant pump of a cooling circuit of a motor vehicle includes a pump chamber, a suction line leading into a suction side of the pump chamber, a discharge channel leading out of a pressure side of the pump chamber, and an electric motor with a controller. The electric coolant pump includes a heater including an electric heating element which projects into the suction line or the discharge channel and which can be flushed by the coolant. The electric heating element includes at least a first heating element operating state in which the electric heating element can be operated from a power supply system and a second heating element operating state in which the electric heating element can be operated from an on-board power supply system of the motor vehicle. The controller of the electric motor is configured or programmed such that the electric motor also includes at least two operating states.

1. FIELD OF THE INVENTION

The present disclosure relates to an electric coolant pump for a coolingcircuit and to a method of operating an electric coolant pump associatedwith a drive assembly of a motor vehicle.

2. BACKGROUND

After a cold start, internal combustion engines initially exhibitreduced efficiency and possibly increased pollutant emissions. Thereason for this, apart from other aspects, is the high viscosity of theoils in this operating state, which cannot yet sufficiently reduce thefriction between the moving oil-lubricated components. For this reason,the basic aim is to heat up the coolant and the engine or transmissionoil quickly. At least for extreme climatic operating conditions, it isnecessary to heat up the coolant before the engine is started.

To heat the coolant, heating elements have so far either been insertedinto the engine block or integrated into existing hose lines.

From the disclosure of DE 103 25 981 A1, it is further known to insertan electric heating element into a suction line of a mechanical coolingwater pump.

WO 2004/011796 A1 shows an electric coolant pump for a cooling circuitof a motor vehicle, which functions as an engine preheater. An electricheating element is arranged in a discharge channel and is flushed by thecoolant. This arrangement of the heating element makes the enginepreheater particularly compact.

DE 10 2017 011716 A1 describes a method for operating an electriccoolant pump and a heating element for preheating a drive train unit ina plug-in hybrid vehicle.

SUMMARY

Example embodiments of the present disclosure provide electric coolantpumps each including a heater to preheat the coolant, which can beoperated efficiently in a simple and environmentally friendly manner.

An example embodiment of the present disclosure provides an electriccoolant pump for a cooling circuit of a motor vehicle including a pumpchamber. The electric coolant pump includes a suction line which leadsinto a suction side of the pump chamber, a discharge channel which leadsout of a pressure side of the pump chamber, and an electric motor with acontroller. The electric coolant pump includes a heater which includesan electric heating element which projects into the suction line or thedischarge channel and can be flushed around by the coolant. The electricheating element includes at least two operating states. In a firstelectric heating element operating state, the electric heating elementcan be operated from an external power supply system, and in a secondelectric heating element operating state, the electric heating elementcan be operated from an on-board power supply system of the motorvehicle. The controller of the electric motor is configured orprogrammed such that the electric motor includes at least two electricmotor operating states. In a first electric motor operating state, theelectric motor can be operated from the external power supply system andin a second electric motor operating state, the electric motor can beoperated from the on-board power supply system. The electric coolantpump includes a first electrical connection to connect to the externalpower supply system and a second electrical connection to connect to theon-board power supply system, the first connection being set up tosupply power to the heating element and the electric motor.

The heating element and the electric motor of the pump can be operatedin an environmentally friendly manner even without a drive assembly ofthe motor vehicle, e.g., an internal combustion engine or a driveelectric motor in the case of electric vehicles. Since the heater is aportion of the pump, the structure is particularly compact. The externalpower grid is not required to be an element of the motor vehicle. Thepower grid can be, for example, a charging station, but also a householdpower connection. No additional connection is required for the heatingelement, which makes the design particularly simple.

Preferably, the electric coolant pump includes a transformer to drivethe electric motor with AC power from the electrical grid.

Furthermore, a motor vehicle is provided with at least one driveassembly and an electric coolant pump described above, the coolant pumpbeing operable to circulate coolant in a cooling circuit of one of thedrive assemblies. In this case, the power supply is preferably anexternal power supply. Preferably, the electric coolant pump includes ahousing which defines a structural element of the drive assembly. Thearrangement thus saves installation space.

Preferably, the at least one drive assembly of a motor vehicle includesa drive electric motor and/or an internal combustion engine.

The motor vehicle may include at least one electrical consumer and anelectrical coolant pump described above, the coolant pump beingstructured to circulate coolant in a cooling circuit of the electricalconsumer. Such an electrical consumer may be, for example, an LED moduleof a motor vehicle headlamp, which is preferably operated at apredefined operating temperature.

Furthermore, an electric motor vehicle may include at least one batterypack and an electric coolant pump described above, the coolant pumpbeing structured to circulate coolant in a cooling circuit of thebattery pack. The battery pack preferably provides power to a driveelectric motor. The efficiency of the battery pack is highly temperaturedependent. The electric coolant pump can heat or cool the battery packso that a desired operating temperature can be maintained.

Preferably, the motor vehicle may include generally internal electricalconnections that provide an electrical connection to the first andsecond electrical connections of the electric coolant pump.

It is preferred if the motor vehicle includes an external electricalconnection that can be connected to an external power supply to supplypower to the heater. In the event that the motor vehicle is a purelyelectric car, it is preferred that the external electrical connection isalso structured to charge the electric car (battery pack).

In addition, an example embodiment of the present disclosure provides amethod to operate an electric coolant pump of a motor vehicle which isassigned to a cooling circuit, the motor vehicle including at least onedrive assembly which is temperature-controlled by the cooling circuit,the electric coolant pump including a pump chamber, a suction line whichleads into a suction side of the pump chamber, and a discharge channelwhich leads out of a pressure side of the pump chamber, and an electricmotor with a controller. The electric coolant pump also includes aheater including an electric heating element that projects into thesuction line or the discharge channel and can be flushed around by acoolant. The heating element includes at least two operating states, afirst heating element operating state in which the electric heatingelement can be operated or is supplied from an external power supplysystem and in a second heating element operating state in which theelectric heating element can be operated or is supplied from an on-boardpower supply system of the motor vehicle, and the electric motorlikewise includes at least two electric motor operating states, a firstelectric motor operating state in which the electric motor can beoperated or is supplied from the external power supply system and in asecond electric motor operating state in which the electric motor can beoperated or is supplied from the on-board power supply system of themotor vehicle. The electric coolant pump includes a first electricalconnection to connect to the external power supply system and a secondelectrical connection to connect to the on-board power supply system,the first connection being set up to supply power to the heating elementand the electric motor.

A procedure according to an example embodiment of the present disclosureincludes receiving a signal that the coolant is to be heated, queryingan operating state of the drive assembly and/or querying whether themotor vehicle is connected to an external power supply, and, if thedrive assembly is not running and/or the motor vehicle is connected toan external power supply, operating the electric heating element and theelectric motor in the first heating element operating state and thefirst electric motor operating state.

Thus, efficient heating of the coolant can take place without the needto run the drive assembly. Both the pump and the heating element arethen supplied with power from an external source. This is particularlyadvantageous for electric cars or hybrid drives, which already have aconnection to an external power grid and which is then preferablyaccessed. The external power grid is preferably not a portion of themotor vehicle. The heating element and the electric motor are thussupplied with power in the first operating state via a connection on themotor vehicle for an external power supply. The power grid can be, forexample, a power charging station, an inductive charging station, butalso a household power connection.

It is advantageous if the controller of the electric motor is set up tocarry out the described process steps. An additional controller can thenbe dispensed with. The heater is then fully integrated in the pump interms of control technology. However, it is also possible to use anadditional separate controller.

Preferably, the electric motor is operated at a low constant speed.

In the event that the combustion engine is running, the electric motoris preferably operated with direct current from a vehicle's electricalsystem.

In an advantageous example embodiment, the signal for heating thecoolant is generated from a signal for a stationary heating operation,i.e., the heater is a portion of a stationary heating operation when thedrive assembly is switched off by operating the pump and the electricheating element.

As previously described, it is preferred if the at least one driveassembly includes a drive electric motor and/or an internal combustionengine. In the event that the motor vehicle is a purely electric car, itis preferred that the external electrical connection is also operable tocharge the electric car (battery pack).

The above and other elements, features, steps, characteristics andadvantages of the present disclosure will become more apparent from thefollowing detailed description of the example embodiments with referenceto the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the present disclosure are described below withreference to the drawings.

FIG. 1 is a schematic representation of an electric coolant pump with anelectric heater according to an example embodiment of the presentdisclosure.

FIG. 2 is circuit diagram of the coolant pump of FIG. 1.

DETAILED DESCRIPTION

FIGS. 1 and 2 show an electric coolant pump 1 in longitudinal sectionalong a pump shaft 2. The coolant pump 1 is provided for circulatingcoolant in a cooling circuit of a drive assembly of a motor vehicle. Thedrive assembly can be an internal combustion engine or drive electricmotor. The two drive types may also be used together in a hybridvehicle. The cooling circuit can then be assigned to one of the twodrive assemblies. The pump shaft 2 passes through the pump housing 3.The pump shaft 2 is driven by means of an electric motor 4 to rotateabout a longitudinal axis 100. The pump housing 3 is formed by a motorhousing 5 surrounding the electric motor 4 or by a housing independentof the motor housing.

A pump chamber 6 is formed in the pump housing 3. A pump element 7 inthe form of a pump impeller 8 is non-rotatably arranged on the pumpshaft 2, lies in the pump chamber 6 and is surrounded by the pumphousing 3. The pump chamber 6 is adapted in shape to the pump element 7.Concentric to the central axis of the pump element 7, a suction line 9in the form of a feed channel opens into a suction side 10 of the pumpchamber. Radial to the center axis 100 of the pump element 7, a pressureline 11 in the form of a discharge channel leads out of a pressure side12 of the pump chamber 6. A heater 13 is arranged in the suction line 9.

The heater 13 has an electrical heating element 14 and an electricalconnection 15, the electrical heating element 14 being connected to theelectrical connection 15. The electrical connection 15 is provided forconnecting the electrical heating element 14 to an external power supplywith alternating current, in particular with 230 volts voltage. Theelectrical heater 13 is attached to the suction line 9 in such a waythat the electrical heating element 14 is surrounded by the coolant inthe suction line 9. When electric power is supplied to the electricheating element 14 via the electric connection 15, the electric heatingelement 14 heats up. The electric heating element 14 heats up thecoolant in the suction line 9. The coolant pump 1 is driven by means ofthe electric motor 4. The pump element 7 rotates and conveys the heatedcoolant, in particular cooling water, from the suction line 9 into thepump chamber 6 and from the pump chamber 6 to the pressure line 11,where it is fed into the coolant circuit of the drive assembly.

The advantage of this arrangement is the accelerated heating of thecoolant when the coolant pump 1 is driven. The existing installationspace of the coolant pump 1 is optimally utilized by the electricalheater 13, which has a simple design. By connecting the coolant pump 1to an external power supply, the power supply can be ensured in anenvironmentally friendly manner even when the engine is switched off orin cold weather.

In general, it may also be envisaged to use the heater in the dischargechannel 11 of the coolant pump 1. In this case, the heated coolant isnot drawn in directly by pump 1, but is fed directly into the coolantcircuit of the drive assembly.

The electric motor is a brushless DC motor comprising a rotor 21connected to a motor shaft 16 and rotatably mounted in the motor housing5. The rotor 21 is provided with permanent magnets. A stator 17 isarranged around the rotor 21, which carries a number of windings on aniron core not shown. When suitably driven, the windings generate amagnetic field which drives the rotor 21 to rotate. The windings areusually wound in three phases and are accordingly provided with threeelectrical connections, via which the windings are connected to acontroller (ECU) 18. The controller 18 is supplied with power from thevehicle electrical system 19 during driving operation.

As shown in FIG. 2, the electric coolant pump 1 is also supplied by theexternal power supply network 15 when the drive assembly is stationary.The heater 13 and a transformer 20 are connected to the power supplynetwork 15. The transformer 20 transforms the input voltage into anoutput voltage adapted to the pump motor 4, in particular 12 volts, 24volts or 48 volts. The electric motor 4 of the coolant pump 1 can beselectively supplied with power from the on-board power supply 19 orfrom the external power supply 15. Switching between the two energysources is performed by means of the controller 18. When the driveassembly is at a standstill, the heater 13 and the coolant pump 1 aresupplied with current by the external power supply system 15. Theelectric motor 4 is operated at a low constant speed so that good heatdissipation and distribution of the heated cooling water can take place.In driving mode and with the drive assembly running, however, theelectric motor 4 is supplied with power from the vehicle electricalsystem 19.

The application range is useful in all water-cooled cars and commercialvehicles and especially in hybrid vehicles, which already have anelectrical connection that can be used to power the coolant pump and theheater.

The electric heater 13 and the coolant pump 1 can be supplied with powerexternally so that efficient preheating of the drive assembly ispossible. Cold-start problems with the internal combustion engine, suchas increased emissions and increased wear, can be reduced or avoided bypreheating the coolant in this way. In addition, warm air can beprovided for interior ventilation at the start of driving, whichincreases driving comfort. It is also conceivable to use the heatedcoolant for stationary heating in the form of a parking heater.

It may also be envisaged to use the electric coolant pump fortemperature control of an electrical load. Many such small,decentralized, electric coolant pumps can be used in a motor vehicle.For example, the coolant may be in thermal contact with an LED module ofa motor vehicle headlight. In the event that the coolant is too cold, itcan be heated by means of the heater.

In another example embodiment, the electric coolant pump is provided forcooling/heating a battery pack of an electric vehicle.

While example embodiments of the present disclosure have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present disclosure. The scope of the presentdisclosure, therefore, is to be determined solely by the followingdisclosure.

1-15. (canceled) 16: An electric coolant pump for a cooling circuit of amotor vehicle, the electric coolant pump comprising: a pump chamber; asuction line which leads into a suction side of the pump chamber; adischarge channel which leads out of a pressure side of the pumpchamber; and an electric motor with a controller; wherein the electriccoolant pump includes a heater which includes an electric heatingelement which projects into the suction line or the discharge channeland which can be flushed by the coolant; the electric heating elementincludes at least two operating states including a first heating elementoperating state in which the electric heating element can be operatedfrom an external power supply system and a second heating elementoperating state in which the electric heating element can be operatedfrom an on-board power supply system of the motor vehicle; thecontroller of the electric motor is configured or programmed such thatthe electric motor includes at least two motor operating statesincluding a first motor operating state in which the electric motor canbe operated from the external power supply system and a second motoroperating state in which the electric motor can be operated from theon-board power supply system; and the electric coolant pump includes afirst electrical connection to connect to the external power supplysystem and a second electrical connection to connect to the on-boardpower supply system, the first connection being set up to supply energyto the heating element and the electric motor in the first heatingelement operating state and the first motor operating state. 17: Theelectric coolant pump according to claim 16, wherein the electriccoolant pump includes a transformer to drive the electric motor with analternating current of the external power supply system in the firstheating element operating state and the first motor operating state. 18:A motor vehicle comprising: at least one drive assembly; and theelectric coolant pump according to claim 16; wherein the coolant pump isstructured to circulate coolant in a cooling circuit of the at least onedrive assembly of the motor vehicle. 19: The motor vehicle according toclaim 18, wherein the electric coolant pump includes a housing whichdefines a portion of the at least one drive assembly. 20: The motorvehicle according to claim 18, wherein the at least one drive assemblyincludes a drive electric motor and/or an internal combustion engine.21: A motor vehicle comprising at least one electrical consumingassembly and the electrical coolant pump according to claim 16, whereinthe coolant pump is structured to circulate coolant in a cooling circuitof the at least one electrical consuming assembly. 22: An electric motorvehicle comprising at least one battery pack and the electric coolantpump according to claim 16, wherein the electric coolant pump isstructured to circulate coolant in a cooling circuit of the at least onebattery pack. 23: The motor vehicle according to claim 18, wherein themotor vehicle includes internal electrical connections providing anelectrical connection to the first and second electrical connections ofthe electric coolant pump. 24: The motor vehicle according to claim 18,wherein the vehicle includes an external electrical connectionconnectable to an external power supply to supply power to the heater.25: A method for operating an electric coolant pump of a cooling circuitof a motor vehicle, the motor vehicle including at least one driveassembly which is temperature-controlled by the cooling circuit, and theelectric coolant pump including a pump chamber with a suction line whichleads into a suction side of the pump chamber and a discharge channelwhich leads out of a pressure side of the pump chamber, and an electricmotor with a controller, the electric coolant pump including a heaterwhich includes an electric heating element which projects into thesuction line or the discharge channel and which can be flushed by acoolant, and the heating element including at least two operating statesincluding a first heating element operating state in which the electricheating element can be operated from an external power supply system anda second heating element operating state in which the electric heatingelement can be operated from an on-board power supply system of themotor vehicle, and the electric motor includes at least two operatingstates including a first motor operating state in which the electricmotor can be operated from the external power supply system and a secondmotor operating state in which the electric motor can be operated fromthe on-board power supply system of the motor vehicle, and the electriccoolant pump includes a first electrical connection to connect to theexternal power supply system and a second electrical connection toconnect to the on-board power supply system, the first connection beingoperable to supply energy for the heating element and the electric motorin the first heating element operating state and the first motoroperating state, the method comprising: receiving a signal that thecoolant is to be heated; querying an operating state of the driveassembly and/or querying whether the motor vehicle is connected to theexternal power supply system; and if the drive assembly is not runningand/or the motor vehicle is connected to the external power supplysystem, operating the electric heating element and the electric motorrespectively in the first heating element operating state and the firstmotor operating state. 26: The method according to claim 25, wherein thecontroller of the electric motor is configured or programmed to executethe method. 27: The method according to claim 25, wherein the electricmotor is operated at a constant speed. 28: The method according to claim25, wherein the electric motor is operated in the second operating statewhen the drive assembly is running. 29: The method according to claim25, wherein a signal to heat the coolant is generated from a signal of astationary heating operation.